Why Clothes Moths Target Your Winter Woollens

There is nothing quite like pulling a favourite jumper out of the drawer on the first cold morning of autumn, only to find a constellation of small holes across the sleeve. Clothes moths are the culprits, and by the time you spot the damage, the infestation has usually been quietly ticking over for weeks.

Unlike the fluttery outdoor moths that batter your kitchen window on a summer evening, the species that ruin clothing are shy and slow-moving. The two you are most likely to meet in a British home are the common clothes moth and the case-bearing clothes moth. Both prefer dim, undisturbed places: the back of a wardrobe, a storage box under the bed, a bag of blankets in the loft.

Crucially, it is not the adult moths that eat your knitwear. The adults do not feed at all. The damage is done by their larvae, which hatch from tiny eggs laid deep in the fibres and then graze on the keratin found in animal-based materials. Wool, cashmere, angora, silk, fur and feathers are all on the menu. Cotton and synthetics are usually left alone unless they are heavily soiled with sweat, food or skin flakes, which is why a stained cotton shirt left at the bottom of a laundry basket can sometimes attract attention too.

Spotting the Early Warning Signs

Moths are masters of discretion, so you need to know what to look for before the holes appear. A quick audit of your wardrobe and linen cupboard a few times a year will catch most problems early.

• Fine webbing in the folds of a jumper, along a seam or in the corner of a drawer. This is often the first visible clue.
• Small, grain-like larvae or the dusty husks they leave behind. Case-bearing larvae drag a little protective tube of silk and fibre around with them, which looks like a tiny grain of rice moving across the fabric.
• Furrows or bald patches on the surface of wool, where larvae have grazed close to the fibres.
• Silvery or golden moths fluttering up when you disturb a drawer. Adults are weak flyers and rarely travel far from their food source.
• Cast skins and dark specks on shelves, which are the remains of larvae and their droppings.

If you find any of these, act quickly. A small, contained population is far easier to deal with than one that has spread through the airing cupboard and into the spare room.

Wash Before You Store

This is the single most effective step, and it is the one most people skip. Larvae are drawn to wool that carries traces of perspiration, skin oils and food spills, so anything going into storage should be genuinely clean. Even a jumper that looks and smells fresh has usually picked up enough body contact over a season to be interesting to a moth.

Check the care label first, then wash accordingly. Many woollens can be washed on a delicate cycle at 30°C with a wool-safe detergent, but if you want to be sure of killing eggs and larvae, you need either a hot wash (check the label carefully) or a spell in a tumble dryer on a warm setting for at least thirty minutes. Dry cleaning also does the job. For delicate pieces that cannot be washed at temperature, sealing them in a plastic bag and placing them in the freezer for seventy-two hours works well, though you should let the item return to room temperature and repeat the process once to catch any survivors.

Dry everything thoroughly before storing. Damp wool invites mould as well as moths, and the two problems together can ruin a blanket beyond rescue.

Store Woollens in Airtight Containers

Once clean, your knitwear needs a barrier between it and any moths still drifting about the house. Clear plastic storage boxes with clip-on lids are ideal, as are vacuum-seal bags for bulky items like blankets and duvets. The key word is airtight. A cardboard box or a cotton pillowcase offers no protection at all, because female moths can squeeze through the smallest gaps to lay eggs directly on the wool.

If you are using vacuum bags, avoid compressing very fine cashmere or anything with delicate embellishments for months on end, as the fibres can crease permanently. For everyday storage, a lidded box in a dry, cool cupboard is perfect. Do not overstuff it; air should be able to move around the garments so nothing stays clammy.

Wardrobes themselves deserve attention too. Give shelves, drawers and the wardrobe floor a thorough vacuum, paying attention to the corners and the runners of sliding doors. Then wipe everything down with a cloth dampened with a little white vinegar or a mild soap solution, and let it dry completely before putting anything back.

Cedar, Lavender and Other Natural Deterrents

Natural repellents will not rescue an active infestation on their own, but they are excellent as a second line of defence once everything is clean and sealed. Moths dislike strong plant oils, and a few well-placed sachets can make your storage areas far less appealing.

• Cedar blocks, balls or rings are the classic choice. Sand them lightly every few months to refresh the scent, and replace them when the aroma fades completely.
• Dried lavender bags are gentler but pleasantly effective, and they leave bedding smelling fresh. Refresh them by crushing the contents occasionally.
• Cloves, rosemary or thyme in small muslin bags work well tucked into drawers, and they combine nicely with lavender in a homemade mixture.
• Cedar-lined drawers or wardrobe panels are a worthwhile investment if you keep a lot of knitwear, since they provide a constant, low-level deterrent.

Remember that these are deterrents, not killers. If you already have larvae in the fabric, scent alone will not solve the problem.

Keeping the Problem From Coming Back

Prevention is mostly about routine rather than heroics. Rotate your knitwear so the same pieces are not left untouched at the back of the drawer for years, and give stored items a quick inspection each season. Vacuum regularly under beds, behind wardrobes and along skirting boards, and keep an eye on any woollen rugs or upholstered furniture, which can harbour larvae just as happily as a jumper.

If you spot adult moths, a pheromone trap placed nearby can help you monitor how many are around and whether your efforts are working. And if you find repeated damage despite your best efforts, it may be worth calling in a professional to treat the room properly and identify the source. With a little care and a good storage routine, your favourite jumpers and blankets will come out of the wardrobe next winter exactly as you left them.